First of all you would need to get clips of frags. You can do this by either recording the player yourself or by asking the player to record themselves and send the demos to you (this is better in a way as it is not possible for you to be able to record 24/7, however, it does take time to sort through good clips).
To record a player, you must be spectating him. Once you have done so, then you press F12, or whichever key is binded to your "/record" command. Once you think you have recorded for a sufficient amount of time, you can press whichever key you binded to "/stoprecord". This demo will be then saved in your "demos" folder in the specific mod file.
Now, most video editing software do not recognize the format of an ET demo file. Thus, you need to re record with a program that saves as a .avi or other supported formats. Luckily, ET does have a play back feature. Now, you need to get a screen capture program, such as Fraps, or Quake Video Maker.
Next step would be to play your demo through ET, which you can do through the main menus, under the option "Replays". Be sure that the mod your demo is in is loaded first and re record it with the screen capture program. Once you have created a recording in a supported format, you may use a video editing software such as Sony Vegas, Cyberlink Power Director (not sure if its the exact name.. its the thingy Rote uses

), Aftereffects, etc...
Once you have successfully edited the movie, you may upload to YouTube or any other media sharing website, and then post the link here, so that we can watch.
This is really brief, but I do hope you get the idea. For a really nice one, take a look at
http://www.crossfire.nu/tutorials/213/moviemaking-a-z